This invention relates to a thermal reactor for treating exhaust gas from an engine of a motor vehicle.
In conventional dual structural thermal reactors, it is necessary to arrange between inner and outer cores and between a shell and said cores such that they are permitted to deform relative to each other due to thermal expansion to prevent their damages. Also, it is necessary to support said cores to prevent production of excessive play therebetween, thereby preventing generations of vibrations and noises.
In order to solve the above technical problems, we have proposed Japanese Pat. Application No. 122728/73 and Japanese U.M. Application No. 133909/72. The former invention relates to a thermal reactor in which one end of the inner core is fixed to one end wall of the outer core and the other end of the inner core is slidably supported on an inner peripheral surface of the other end of the outer core. The latter invention is such that the outer core is formed from two outer core members joined to each other through the flanges integrated therewith, said flanges being supported in a groove provided on an inner periphery of the shell of the thermal reactor with a space so as to permit the thermal expansion of the outer core.
We have made various tests on the thermal reactor in which both of said inventions are combined and in which the inlet pipe fixed to the shell is slidably inserted through said outer and inner cores and the outlet pipe fixed to the outer core is slidably supported in an outlet opening in the shell. As a result, it has been experienced that abnormal wear and unpleasant noise are generated at the sliding portions between the shell and the outer core and between the outlet pipe and the shell because of the vibrations of engine and vibrations generated upon running of the vehicle, since said cores are floatingly suspended within the shell. That is to say, the cores, the shell and the inlet pipe, and the outlet pipe have no fixed portion, which is a based point upon relative movements therebetween due to the thermal expansion. Therefore, the cores are retained in floating conditions within the shell to produce play at sliding portion of each member by vibrations generated during running of the vehicle and operation of the engine, thereby causing vibrations and abnormal noises, and further increasing wear at each sliding portion. Also, it has been experienced that the exhaust gas from the engine enters directly into a space between the outer core and the shell and then is discharged to the atmosphere without reburning of the exhaust gas within the inner core, because after a long period of use play is produced at the sliding portions between the inlet pipe and an inlet portion of the shell and between the outlet pipe and an outlet portion of the shell.
This invention is to provide an improved thermal reactor in which the above drawbacks in the inventions of our aforementioned applications are avoided.